1. Field of the Invention
The present invention relates to an electronic module and a communication apparatus including the electronic module. In particular, the present invention relates to an electronic module including a mount board including one main surface on which an electronic component is mounted and another main surface including a portion which is covered with an insulating layer, and to a communication apparatus including the electronic module.
2. Description of the Related Art
For example, electronic modules in which an electronic component, such as a capacitor, an inductor, a high-frequency filter, or a semiconductor element, is mounted on a resin board or a ceramic board have been widely used. An example of such an electronic module is described, for example, in Japanese Unexamined Patent Application Publication No. 2002-43368.
FIG. 12 is a schematic sectional view of the electronic module described in Japanese Unexamined Patent Application Publication No. 2002-43368. As illustrated in FIG. 12, an electronic module 100 includes a semiconductor element 101, which is one type of electronic component, and a substrate 102 including one main surface 102a on which the semiconductor element 101 is mounted. On the other main surface 102b of the substrate 102, a plurality of electrodes 103 that are connected to the semiconductor element 101 are formed. The plurality of electrodes 103 include a ground electrode that is connected to the ground potential and a signal electrode that relates to input and output of signals. In the electronic module 100, a solder resist layer 104 is formed on the main surface 102b of the substrate 102. The solder resist layer 104 covers peripheral portions of all the electrodes 103. Accordingly, the plurality of electrodes 103 are not short-circuited. Soldering balls 105 are formed on the individual electrodes 103.
However, in the case of the electronic module 100, in which the peripheral portions of all the electrodes 103 are covered with the solder resist layer 104, there is a problem in which the electrical characteristics of the electronic module 100 degrade.